This invention relates to printed wiring boards (PWBs), and has particular relation to apparatus and methods for developing PWBs for systems.
A printed wiring board (PWB) is generally part of a larger system. Development of the PWB generally runs concurrently with development of the remainder of the system. It often happens that a step in the development of the system does not require any change in the components or function of the PWB, but does require a change in the interface between the PWB and remainder of the system. For example, the interface may be the terminal of a cable with dozens of separate wires, each of which connects to a separate pin on the PWB. On the PWB, the component which used to connect with pin A now must connect to pin B, another component which used to connect with pin B must now connect to pin C, and a third component which used to connect with pin C must now connect to pin A. This pin reconfiguration is required by the reconfiguration of whatever device the other end of the cable was connected to.
When the user makes the next iteration of the system under development, he must prototype the entire system, and that means that he must prototype the PWB. The new prototype of the PWB has the same components and function as the previous prototype, and yet the (expensive) old prototype must be discarded and an (expensive) new prototype must be built, even though the only difference is a pin reconfiguration. This seems wasteful, but has been accepted as a necessary part of PWB development.
Applicant has eliminated this waste with a bi-directional interface tool. A first printed wiring board (PWB) has a first set of parallel printed wires on one face and a second set of parallel printed wires on the other face. The second set is generally orthogonal to the first set. The first set terminates in a first adaptor, which mates with an interface (such as the plug or socket, or other terminal, of a cable) having many parallel channels (such as wires). The second set terminates in a second adaptor, which mates with a second PWB. Alternatively, the first adaptor mates with a third adaptor on the second PWB, and the second adaptor mates with a fourth adaptor on the second PWB.
Development of the second PWB is enhanced when any input or output on the second PWB can be connected to any channel of the interface. Thus, a hole is drilled through the first PWB at the intersection of the appropriate printed wires of the first and second sets, and is plated. The plated hole may be drilled out (rendering it non-conductive) and effectively replated (or, preferably, filled or refilled) many times. Alternatively, the (inexpensive) first PWB may be replaced.